Grinding apparatus



June 4, 1940.

S. A. HAMNETT GRINDING APPARATUS 2 Sheets-Sheet 1 Filed Aug. 29, 1938 INVENTOR. 6A. HA MNETT ATT June 4, 1940. s HAMNETT 2,203,262

I GRINDING APPARATUS I Filed Aug. 29, 1938 2 Sheets-Sheet 2 I NVENTOR. 5. A. HA MNE TT Yatented June 4, 194% 2,203,262 GRINDING APPARATUS Samuel A. Hamnett, Los Angeles, Calif.

Application August 29, 1938, Serial No. 227,256

Claims. I

This invention relates to grinding apparatus. The generalobject of the invention is to provide an improved tool grinding apparatus.

A more specific object of the invention is to 5 provide a novel tool grinding machine particularly adapted accurately to produce facets on a die sinking tool.

Another object of the invention is to provide a tool grinding apparatus having novel means to 1: hold, rotate and reciprocate the work in relation to a rotating abrasive wheel.

Another object of the invention is to provide a tool grinding apparatus adapted to produce various shapes and numbers of facts on a die sinking tool.

Another object of the invention is to provide a tool grinding machine having novel means for trueing the abrasive member.

A further object of the invention is to provide novel means for mounting an abrasive wheel.

Other objects and advantages of my invention will be apparent from the following description taken in connection with the accompanying drawings, wherein:

Fig. l is a top plan view of a tool grinding apparatus embodying thev features of my invention;

Fig. 2 is a section taken on line 2-2 Fig. 1;

Fig. 3 is a section-taken on line 3--3 Fig. 2;

Fig. 4 is a section taken on line 4-4 Fig. 1;

Fig. 5 is a fragmentary rear view of the apparatus shown in Fig. 1;

Fig. 6 is a section taken on line 6--6 Fig. 5;

Fig. 7 is a section taken on line 1-1 Fig. 5;

Fig. dis a section taken on line B-8 Fig. l; and

Fig; 9 is a vertical section through the pivot between the support and sector plate.

Essentially my invention includes a rotative abrasive wheel, means to hold a tool to be ground, and means to impart various relative motions between the wheel and the tool.

Referring to the drawings by reference characters I have shown my invention as embodied in a tool grinding apparatus indicated generally at l6. As shown the apparatus H3 includes a base plate it having integral therewith a hollow upstanding support l2 with a cross section subs'tantially in the form of a sector of a circle. The support 12 has a plane upper face [3 having suitable strengthening ribs M disposed therebelow and further includes a portion 15 laterally ex tending from the face (3 at the intersection of the bounding radii thereof.

Slidably engaging the face I3 is a sector plate it pivoted thereto as at H. As shown in Fig. 9 the pivot 11 includes a pin it passing through the plate l6 and the extending portion 15 and having an enlarged head 26 and a lower threaded l9 engaging the plate portion carrying nuts 2% to hold the plate in engagement with the extending portion IS. A cover plate 22 tioned above the head plate it as by screws 23.

is posil9 and is secured to the The sector plate It has a portion having a reduced radius and a beveled arcuate edge 28 engaged by a clamp member 25 attached to the face 63.

As shown in Fig. 4 the clamp 25 in-' cludes a dog 26 and has a screw 21 engaging the support the head thereof engageable by a key 29.

To move the sector plate is provided while the beveled edge 24 I2 and having a square aperture 28 in IS a radial handle 3 may be graduated to indicate the position in which the plate is arranged. Radial wipers 3i and 32 are positioned on the plate l6 and a is positioned on the support 12.

similar wiper 33 Each wiper consists of a felt strip 34 secured by a plate 35 and screws 35.

The wipers prevent harmful substances such as abrasive dust and chips from entering between the face l3 and the sector plate It.

Disposed upon the sector plate It are a pair of ways Ml slidably supporting a bed 4! carrying an electric motor 42 having an abrasive wheel 13 mounted on the shaft thereof. The

are so positioned that the plane of the wheel 43 :3

ways it remains radial in respect to the sector plate i5 irrespective of The bed 4i may be moved along the the position of the bed 4| ways it) by the rotation of a screw 45 supported as at it and 41 and engaging a half nut member ts a manually operable knob 52.

As shown in Fig.

5 the shaft 5| is rotatable within anti-friction bearings 53 positioned within a cylindrical casing 54 attached to the sector 5| and above the casing plate l6.

engaging the shaft 51 by a set screw 56.

On the shaft 54 is a conical collar 55 It will be seen that rotation of the knob 52 will cause the bed M to move upon the ways 40: the position of the bed may be indicated by graduations on the conical collar 55.

Positioned on the extending portion l 5 I provide an upstanding hollow boss 51. engaged by a plunger 58 carrying at its upper end a chuck I assembly 59. The assembly 59 floats on 59 on the plunger 58.

the extending portion 15 are ways '60 a spring Attached to one side of engaged thereto and by a slide 6| which is secured adjacent its upper end to the chuck assembly 59. The slide 6| may be fixed in position by a screw 62 threadedly engaging one of the ways 60 and impinging upon a gib 63 engaging the slide 6!;

As shown in Fig. 6 the chuck assembly 59 includes a hollow body portion 64 which is split as at 65. With the body portion 64 is a hollow cylinder 66 having an anti-friction bearing 6? disposed within each end thereof. The inner races of the bearings 81 engage a hollow core member 68 within which is disposed a collet 68 having a central bore 59, an externally threaded end 10 and a conical head H split in the usual manner as at 12. A manually operable knob 13 engages the threaded end 70 and serves to draw the conical head ll into a conical bore 14 within the core member 68 closing the collet about a tool 15. The core member 68, including the collet and tool, may be rotated by a disk I6 rigidly attached having suitable spaced depressions Tl on one face engageable by a ball 18 urged thereinto by a spring 19.

As shown an electric motor 80 is positioned on the base plate I l within an aperture 8i in the support l2 and rotates a cam 82 through a suitable reduction gearing. The cam 82 engages a roller 83 disposed on the lower end of the slide 6! and when the screw 62 is released reciprocates the chuck assembly 59 and the tool 15 tangentially to the wheel 43.

A device 84 for restoring the truth of the wheel 13 is secured to the sector plate It by an upright support 85. As disclosed the device 84 includes a diamond point 88 on an arm 87 attached to a block 88 slidable on a pair of parallel arms 85 secured to the support 85. The block 88 is moved upon the arms 89 by means of a screw 90 operated by a crank and handle assembly 9| as clearly indicated in Figs. 1, and 8. The wheel 43 is brought into engagement with the diamond by means of the sliding bed M, and the diamond is then fed laterally across the periphery of the Wheel, the path of the diamond being parallel to the axis of the wheel.

From the above description it will be seen that I have provided various relative movements between the abrasive wheel and the tool to be ground: the wheel may be moved to and from the tool by the sliding bed 44; the wheel may be pivoted about the tool by rotating the sector plate; the tool may be reciprocated tangentially to the wheel; and the tool itself may be rotated. With this combination of motions a large variety of tool shapes may be conveniently produced.

From the above description it will be apparent that I have invented a tool grinding machine that is highly efficient for its intended purpose.

Having thus described my invention, I claim:

1. In a grinding apparatus, a base plate, a horizontal sector shaped support integral with the base plate, said support having a plane upper'face, said support including a laterally extending portion at the intersection of the bounding radii of the sector, a pivot pin passing through said laterally extending portion, a sector plate having a hole therein receiving said pin, a clamp member on said support adapted to hold the sector plate in adjusted position, a bed slidable on said sector plate, a motor on said bed, said motor including a shaft, an abrasive wheel on said shaft and disposed so that the plane of the middle portion thereof is co-incident with the vertical plane which passes through the pivot pin and is parallel with the said one edge, a casing on said sector plate, a horizontal shaft extending from said casing, means to drive said last mentioned shaft, said last mentioned shaft including a threaded portion, threaded means on said bed engaging said threaded shaft portions, a chuck assembly slidable on said support, a plunger slidable on said support, said chuck assembly engaging said plunger and means to move the chuck assembly.

2. In a. grinding apparatus, a base plate, a horizontal sector shaped support integral with the base plate, said support having a plane upper face, a pivot pin on said support at the intersection of the bounding radii of the sector, a sector plate having a hole therein receiving said pin, said sector. plate having an arcuate outer edge with one portion having a beveled edge, a clamp member on said support adapted to engage said beveled edge to hold the sector plate in adjusted position, a pair of ways on said sector plate and disposed parallel to one edge of the sector plate, a bed slidable on said ways, a motor including a shaft, an

through the pivot pin and is parallel with the said one edge, a cylindrical casing on said sector plate, a vertical shaft in said casing, a horizontal shaft extending from said casing, gear means connecting said shafts, said horizontal shaft including a threaded portion, threaded means on said bed engaging said threaded shaft portion, a boss on said support, other ways on said support, a slide engaging said last mentioned Ways, a chuck assembly on said last mentioned slide, a plunger slidable on said boss, said chuck assembly engaging said plunger, spring means to float the chuck slide and cam means to move the chuck assembly.

3. In a tool grinding apparatus, a base plate, a horizontal sector shaped support integral with said base plate, said support having a plane upper face, said support including a laterally extending portion at the intersection of the bounding radii of the sector, a pivot pin passing through said laterally extending portion, a sector plate having a hole therein receiving said pivot pin, said sector plate having an annular outer edge with one portion of the outer edge of reduced diameter, said reduced portion having a beveled edge, a clamp member on said support adapted to engage said beveled edge to hold the sector plate in adjusted position, a handle on said sector plate, a pair of ways on said sector plate and disposed parallel to one edge of the sector plate, a bed slidable on said ways, a motor on said bed, said motor including a shaft, an abrasive wheel on said shaft and disposed so that the plane of the middle portion thereof is co-incident with the vertical plane which passes through the pivot pin and is parallel with the said one edge, a cylindrical casing on said sector plate, a vertical shaft in said casing, hand operated means for rotating said shaft 2. horizontal shaft extending from said casing, gear means connecting said shafts, said horizontal shaft including a threaded portion, threaded means on said bed engaging said threaded shaft portions, a boss on said laterally extending portion, ways on said laterally extending portions, a slide engaging said last mentioned ways, a chuck assembly on said last mentioned slide, a plunger slidable on said boss, said chuck assembly engaging said plunger, spring means to float the chuck slide and cam means to move the chuck slide.

4. Ina tool grinding apparatus, a horizontal base, an upwardly extending sector shaped support integral with said base, said support having a plane upper face and having stifiening ribs thereon, said support including a laterally extending portion disposed substantially at the intersection of the bounding radii of the sector, a pivot pin passing through said laterally extending portion and having an enlarged head thereon, a sector plate having a hole therein receiving said pivot pin and its head, a fastening means engaging the lower end of the pivot pin and the lower face of the laterally extending portion,

said sector plate having an arcuate edge with one portion of the outer edge of reduced diameter,

' said portion of reduced diameter having a beveled edge, a clamp member on said support and having a face adapted to engage said beveled edge to hold the sector plate in adjusted position, a

handle on said sector plate, wiper members on ated means for rotating said shaft, a horizontal shaft extending from said casing, gear means connecting said shafts, said horizontal shaft including a threaded portion, threaded means on said bed engaging said threaded shaft portions, a boss on said laterally extending portion, ways on said laterally extending portions, a slide engaging said last mentioned ways, a check assembly on said last mentioned slide, a plunger slidable on said boss, said chuck assembly engaging said plunger, spring means to floatthe chuck slide and cam means to move the chuck slide.

5. In a tool grinding apparatus, a base, means on the base to support a tool to be ground, a sector plate pivotally mounted on said base with the axis of the nivot substantially co-incident with the tip of a tool on the tool support, a pair of ways on said sector plate, a bed slidably engaging said ways, a motor on said bed, said motor having a shaft, an abrasive wheel on the shaft, the axis of the pivot being disposed between the planes of the faces of the abrasive wheel, a truth restoring member, said member including a support mounted on said sector plate, a pair of parallel arms secured to said support, a reciprocating block mounted on said arms, a cutting point on said block, said block having a threaded aperture, a threaded shaft engaging the threaded aperture in said block, means to rotate said threaded shaft to thereby shift the block, said cutting point being in the path of movement of the abrasive wheel.

SAMUEL A. HAMNETT. 

